Romney Adds to Delegate Lead in Illinois Primary

WASHINGTON — Former Massachusetts Gov. Mitt Romney added to his lead in the race for delegates Tuesday with his victory in the Republican presidential primary in Illinois.

Romney won at least 19 delegates in Illinois, with 35 still to be determined.

Illinois has a unique system of awarding delegates to candidates. The delegates are not determined by the statewide vote. Instead, individual delegates are listed on the ballot in each of the state's 18 congressional districts. They are identified by the candidate they support.

Former Pennsylvania Sen. Rick Santorum was at a disadvantage because only 44 of his delegates qualified for the ballot.

Romney leads the overall race for delegates with 541, including endorsements from Republican National Committee members who automatically attend the convention and can support any candidate they choose.

Santorum has 253 delegates, former House Speaker Newt Gingrich has 135, and Texas Rep. Ron Paul has 50.

It will take 1,144 delegates to win the Republican nomination to take on President Barack Obama in the fall.

So far, Romney has won 54 percent of the delegates at stake in primaries and caucuses. That puts him on pace to clinch the nomination in June, but it doesn't leave much room for error.

Santorum has won 27 percent of the primary and caucus delegates at stake so far. He would need to win 73 percent of the remaining delegates to clinch the nomination before the party's national convention in August.